Analysis and assessment of slope instability along international mountainous road in North Africa

Multi‐temporal InSAR analysis to monitor landslides using the small baseline subset (SBAS) approach in the Mila Basin, Algeria

“…Ground truth data resulted from the slide happened after 17 July and August 7, 2020 earthquakes. Letters (a–c) express the sliding and groundwater seepage (d) that were observed at Grarem Gouga exactly on the highway N27 (this image is modified after Ogila (2021)). On the contrary, minor deformation happened at area (e) at Sibari region resulted in small‐scale cracks…”

“…(top) The plots of deformation velocity rate acquired from horizontal (blue dots) and vertical (red dots) components compared with elevation profiles of intersections (black lines) drawn in Figures 6 and 8. (bottom) profiles of A‐A' and B‐B′ showing the geological cross section based on landslide's morphology (Takada & Motono, 2020), elevation and boreholes (Athmania et al, 2010; Ogila, 2021) information at Mila (a) and Grarem Gouga (b) cities…”

“…However, during the time period between the two seasons (April to June and September to November), our investigated areas became stable. See the unshaded zone in Figure 11 (North et al, 2017; Ogila, 2021; Xu et al, 2020).…”

“…The lithological feature of a sub‐clay layer extends to 9 m at Grarem Gouga, contrary to Mila city with a clay layer thickness of 150 m. The clay layer overlies a base layer composed of marly limestone. Moreover, saturation of the clay beneath the water table ranges in depth from the ground surface to 3 m in Grarem Gouga and 10–15 m in Mila (Athmania, Benaissa, Hammadi, & Bouassida, 2010; Ogila, 2021). The study area has an annual precipitation of approximately 600 mm/year, with heavy rainfall in winter, from October until March, and extreme drought in summer (wet‐dry seasons), from June until the end of August (Athmania et al, 2010).…”

“…The study area has an annual precipitation of approximately 600 mm/year, with heavy rainfall in winter, from October until March, and extreme drought in summer (wet‐dry seasons), from June until the end of August (Athmania et al, 2010). As the shape of the slide surface can be described from the geotechnical properties of the soil (Zhou, Shi, & Xu, 2013), extensive laboratory investigations have been conducted (Ogila, 2021) to assess the slope instability and safety factors in the north‐east region of Algeria. These investigations revealed the geotechnical characteristics of the sub‐base layers composed of clay and marly limestone.…”